The present invention relates to a portable liquid dispensing device for subcutaneous, intravenous and similar feeding of liquids such as medicaments and the like.
We have previously disclosed in our U.S. Pat. No. 4,447,232, issued on May 8, 1984 (commonly assigned to the assignee hereof) a portable liquid dispenser particularly adapted for the constant rate feeding of medication and the like to fully ambulatory patients. The apparatus disclosed in the aforesaid patent has had wide commercial success and is in use throughout the world.
In this patent, a collapsible bag is located along with a piston-like slide member in a housing. A constant force spring acts on the slide member to exert a constant pressure on the bag. The front cover of the housing is provided with a slot, while the slide member is provided with a rectangular lug passing through the slot. The slot and lug provide tracking and alignment to the slide member since the lug which fits (with tight tolerances) into the slot prevents rotation of the slide member. A clip, which is a part of a fitting on the case, permits the lug to be locked and thereby removes pressure from the fluid reservoir.
This worked quite well, although somewhat complexly to produce. Also, the external clip extended beyond the surface of the housing which increased the overall thickness of the device. In addition, when worn on the body, the lug and clip tended to snag on clothing or undergarments and could not be concealed in a trouser pocket. The slot, furthermore, constituting an opening through which the liquid bag was visible represented an external channel through which contamination and damage to the bag could occur. Thus, the need to simplify the construction of such a device is apparent to render it more easy to use, to lower the cost thereof, and to provide greater reliability and greater accuracy in dose dispensing.
It is, therefore, the object of the present invention to provide an improved liquid dispensing device for subcutaneous, intravenous, and/or similar medicament feeding characterized by its simplicity of construction, ease of operation and great reliability.
The foregoing objects, together with numerous other objects and advantages will be apparent from the following disclosure.